I can totally understand the feelings of apprehension when you read the posts about issues with the new iMacs with ATI cards. When you are ready to make a big investment, it is not a great feeling to start reading about what appears to be a legitimate issue.
On the other hand, I would not write off purchasing a Mac altogether.
Personally I have been on the Windows/DOS platform (primarily) as a user and developer since the days of the 286 (having reluctantly given up my Commodore computers...). I have owned some Macs off and on throughout the years - but for the most part Windows had always been my primary OS. Because of this, I hardly consider myself a Mac fanboy or fanatic.
Right now, the other computer we have in the house is an HP Core 2 Quad 2.66Ghz with 8GB Ram and a Nvidea 8800 GT GPU. It's a great computer and we have had no issues with it for about a year. That computer, currently, is functioning as a Media Center PC as well as a general use computer for my wife and the kids.
I am writing this message on a recently purchased iMac 24" 2.8Ghz, 4GB, ATI 2600 GPU. I purchased it as a refurb from Apple for $1199. Initially I was a little hesitant about going from a Quad Core 8GB machine down to a Dual Core 4GB machine, as my primary computer.
I was expecting to notice a little more sluggishness on the iMac compared to my Quad Core - but I am truly amazed. I am sure it has everything to do with OS X, and nothing to do with the hardware - but my new iMac does not miss a step, and feels FASTER than the HP Quad Core 8GB machine running Vista Ultimate 64 bit.
Everyday I learn something new about OS X, and I am amazed at the productivity enhancements that are available in the OS compared to Windows (like Spaces for instance). Right now, a couple of weeks into owning my first All-In-Once PC (which I thought I was going to hate) and the first Mac in some years, I have to say I may never go back to Windows again.
So, I guess what I am trying to say is that OS X performs so well, that maybe a 3.06Ghz with the 4850 is not necessary. I can understand that everyone want to have the latest and greatest - but if I lived in a country that has to pay 250% more - I think I would be looking at Macs that were on the lower scale, anyway, so that the 'penalty' would be less severe.
From my experience on my new iMac, I can definitely say that if I was looking at the 3.06 w/4850 and decided against it (under current conditions I probably would feel the same as you), I would be happier going with a high end refurb - than going to a PC. The difference between Windows and OS X is night and day. If you really decided to get a Mac, I think you should.
Recently Apple has had 2008 24" 3.06Ghz iMacs with the Nvidea 8800 GPU for $1599. Sure the GPU is not the same as the 4850 - but the iMac is a significant discount, and with you having to pay 250% more - the savings would be quite significant. Plus it seems that the 2008 iMacs were pretty reliable and I haven't read of a lot of issues with them. I think for most things, except for games, the experience would be quite similar, and you can save some money and be reasonably confident that you will receive a machine with the quality that you are looking for. I have the model down from that one and I am more than pleased with it compared to my other Quad Core machine running Vista, and I wouldn't even dream of switching this iMac out from being my new primary PC.
Anyway good luck to everyone who is considering the new iMac 3.06 w/ ATI 4850. I tend to over analyze all of my purchases and I can definitely understand that some have become a little 'spooked'. If it were me, I would probably go with a high end refurb and sell it next year and pick up a 3.06 w/ATI 4850 (if I decided I really needed it) after the bugs had been worked out. With Apple's commanding pretty good resale value, and the possibility of new iMac upgrades next year, it might end up costing the same in the long run...
Good luck all..
releases, 
